In certain imaging systems, such a cameras on mobile computing platforms, silicon (Si) based image sensors, such as charge couple device (CCD) or complementary metal oxide semiconductor (CMOS) image sensors, may be used for image capture. The bandgap of Si, at Eg=1.1 electron volts (eV), corresponds to 1125 nanometers (nm) wavelength, which is within the near-infrared (NIR) spectral region. Therefore, the Si material of Si-based image sensors are sensitive up to a wavelength of about 1125 nm. The spectral sensitivity of these Si-based image sensors may correspond to an optical wavelength range from about 350 nm to about 1125 nm. This may enable the acquisition of spectral information at the visible spectral range corresponding to wavelengths of about 380 nm to about 780 nm and the NIR spectral range corresponding to wavelengths of about 780 nm to about 1125 nm.
For most applications, the spectral information associated with a visible range of wavelengths of about 380 nm to 780 nm is used to generate images. In these applications, the capture of NIR spectral information may introduce haze, noise, or otherwise degrade the image in the visible spectral range. Therefore, Si-based image sensor often have NIR filters provided thereon to prevent the detection of radiation in the NIR frequency range for most applications. The NIR filters, by design, filter out spectral information that may otherwise be captured by the Si-based image sensor. Furthermore, the NIR filters may introduce merit, such as processing and/or material merit during manufacture of the Si-based image sensors.